Position velocity diagram of the Par-Lup 3-4 jet in [S II]λ6731 with the velocity centroid measured at various positions along the jet marked (red crosses). Right panel: line profiles corresponding to each red cross. Contours begin at 1.5 × 10^-18 erg/s/cm² and increase logarithmically to 68 × 10^-18 erg/s/cm². Velocities are systemic. The extraction window for the spectra of the blue and red jets are also shown. The fluxes of the lines which are detected in these regions of the jets are given in Table A.2. The Par-Lup 3-4 jet is fairly symmetric and clearly the velocity of both lobes increases with distance from the source. Comerón & Fernández (2011) note the presence of a small red-shifted knot at ~–2.̋5 which is also seen here.